Egypt's prosecutor-general has started routine procedures to arrange an appeal for Monday's verdict upholding the death penalty for 37 people and sentencing 492 others to life in prison, a statement from the prosecutor's office said.

The 529 defendants were initially given a mass death sentence on 24 March, the biggest in Egyptian legal history, before it was reduced for most of them on Monday.

The prosecutor's appeal will include the sentences granted on 24 March, including the acquittal of 17 defendants, and the latest sentences of death and life imprisonment given on Monday.

The appeal is a routine procedure after any final death sentences.

The prosecutor's statement cited its concern for the "the proper administration of justice and application of the correct law" and stressed that it was utilising a routine procedure of appeals for death sentences in Egypt.

The 529 people were accused of attacking a Matay police station in south Egypt and killing a police officer on 14 August 2014, as part of the eruption of nationwide violence following the dispersal of two Cairo sit-ins for ousted president Mohamed Morsi.

They were also accused of destroying public and private property, joining a banned group, rioting and inciting violence. 

Monday's verdict was announced after Egypt's Grand Mufti finished reviewing the original 529 death sentences.

The Grand Mufti's view is not binding but must be sought before death sentences are carried out.

Lawyers of the 37 people sentenced to death said they would also appeal the verdicts.

In a separate trial, the same court on Monday sentenced 683 people to death for attacking an Adawa police station and killing an officer, also after the violent dispersals in August.